People may not answer calls to their mobile phones for a variety of reasons. For example, they may be attending an important meeting, driving a car, or traveling. Typically, the caller reaches the callee's voicemail, which prompts the caller to leave a message or to try calling back later. However, the generic greetings of a voicemail typically do not inform the caller of the reason for the callee's failure to answer the call during that particular event. Consequently, the callee may feel anxious or ignored. On the other hand, the phone calls may disrupt a meeting, distract a driver, or otherwise put undue pressure on the callee to return the calls.